TRUTH TABLE 1

Selection

ACTIVE LOW DATA

M = H Logic

Functions

M = L: Arithmetic Operations

S3

S2

S1

S0

Cn = L (no carry)

Cn = H (with carry)

L

L

L

L

F = A

F = A Minus 1

F = A

L

L

L

H

F = AB

F = AB Minus 1

F = AB

L

L

H

L

F = A + B

F = AB Minus 1

F = (AB)

L

L

H

H

F = 1

F = Minus 1 (2’s Compl)

F = Zero

L

H

L

L

F =A+B

F =A Plus (A + B)

F = A Plus (A + B) Plus 1

L

H

L

H

F = B

F = AB Plus (A + B)

F = AB Plus (A + B) Plus 1

LH

H

L

F = A

⊕ B

F = A Minus B Minus 1

F = A Minus B

L

H

H

H

F = A + B

F =A+B

F = (A + B) Plus 1

H

L

L

L

F = AB

F = A Plus (A + B)

F = A Plus (A + B) Plus 1

HL

L

H

F = A

⊕ B

F = A Plus B

F = A Plus B Plus 1

H

L

H

L

F = B

F = AB Plus (A + B)

F = AB Plus (A + B) Plus 1

H

L

H

H

F = A + B

F =A+B

F = (A +B) Plus 1

H

H

L

L

F = 0

F = A Plus A *

F = A Plus A Plus 1

H

H

L

H

F = AB

F = AB Plus A

F = AB Plus A Plus 1

H

H

H

L

F = AB

F = AB Plus A

F = AB Plus A Plus 1

H

H

H

H

F = A

F = A

F = A Plus 1

* Each bit is shifted to the next more significant position.

FIGURE 1

M74HC181

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